Does a leave-purchase or sabbatical savings scheme get used outside head office?

Insurance company in the Netherlands, around 2,200 employees. We are looking at letting people save up to 100 weeks of leave over time, funded from unused holiday and salary, to take as a sabbatical or to wind down before retirement.

Our worry is that it becomes a benefit for well-paid people in head office who can afford to forgo pay, while call centre and claims staff never touch it. We also have managers who say they could not release anyone for three months.

If you run something similar, who actually uses it and for what?